Four years after his unlikely smash The Full Monty sparked a seemingly insatiable interest in the world's quirky underclass, director Peter Cattaneo finally returns for a victory lap with the brisk, disposable prison comedy Lucky Break. In the downtime, he seems to have forgotten his roots: The Full Monty may be remembered more for its sweetly inelegant striptease than for its blue-collar backdrop, but Cattaneo found a way to soften and popularize the working-class grit of directors like Mike Leigh and Ken Loach. With Lucky Break, he scraps the social commentary and sticks to the cute, coasting on a formula that's been worn thin by Billy Elliot, Greenfingers, Waking Ned Devine, Bootmen, and countless other Monty knock-offs. Smooth and diverting as far as it goes, the film's one-joke premise (jailhouse ruffians put on a lavish musical) reveals so little ambition on Cattaneo's part that he's politely asking audiences to pay for the same movie twice. The affable James Nesbitt leads a capable cast as an incompetent career criminal who lands a long-term jail sentence after he and his best friend (Lennie James) botch a bank-robbery attempt. Soon restless behind bars, in spite of the apparent coziness of the British penal system, Nesbitt finds an easy escape route adjacent to an old prison chapel that's scheduled for demolition. Playing on genial warden Christopher Plummer's weakness for South Pacific and other Broadway shows, he convinces his fellow inmates to stage Plummer's original musical production in the chapel and scale the wall before taking their bows on opening night. Among the stock charactersincluding a sadistic guard (Ron Cook), a Brecht-quoting highbrow director (Julian Barratt), and several genial thugsLeigh regular Timothy Spall and Rushmore's Olivia Williams add a few grace notes as Nesbitt's melancholic cellmate and love interest, respectively. But no one overexerts himself in Lucky Break, which plays out without a single surprise and never attempts even the simple comic invention of the unemployment-line boogie in The Full Monty. Many of the gags are just too familiar, like having the meanest-looking brute tend to a patch of prize tomatoes, a painfully obvious irony that was the entire basis of Greenfingers. And the big musical setpiece, rife with possibilities for humor and uplift, needed to be funnier and more energetic than the half-hearted lyrics and choreography bother to muster. In returning to the same well, Cattaneo implies that nothing can stop a winning formula, no matter how apathetic in spirit.